The symmetrical, malonodiserinolamide hexa-substituted [60]fullerene, C₆₀‑ser, is a key water-soluble C₆₀ derivative of interest for the treatment of cancer by radiofrequency(RF)-induced hyperthermia due to its biocompatibility, neutral charge, lipophilicity, and ability to cross restrictive biological membranes. In aqueous solution C₆₀-ser, which is surrounded by 24 hydroxyl groups, maintains relatively stable layers of closely-bound water molecules (hydration sphere), forms highly dynamic aggregates, sized between 100-400 nm in diameter, which exist in equilibrium with individual, hydrated C₆₀-ser molecules. Our recent observations indicate that these dynamic C₆₀-ser aggregates are built up of a single layer of C₆₀-ser molecules, with water locked inside a hollow core structure. Using a thermal imaging camera, aqueous C₆₀-ser solutions have been shown to produce heat when irradiated with an 13.56 MHz RF field (900W) in a concentration-dependent manner with a heating rate of up to 1.0 °C/sec at 10 mg/ml. This result establishes that C₆₀‑ser is a neutrally-charged, key [60]fullerene-based nanoparticle, that might be used for the treatment of cancer by RFH-induced hyperthermia.

We acknowledge Kanzius Foundation and Welch Foundation Grant C-0627 for financial support.